A Story of Numbers | FIO

Question 11

Write the following numbers in the above base-5 system using the symbols in Table 2: 15, 50, 137, 293, 651.

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Solution

We will express each number as a sum of powers of 5, using the given symbols.

Step 1 — Understanding the Symbols

Let us first list the value of each symbol from the provided table. The symbols represent powers of 5. =50=1\triangle = 5^0 = 1 =51=5\square = 5^1 = 5 \hexagon=52=25\hexagon = 5^2 = 25 =53=125\bigcirc = 5^3 = 125 =54=625\sim = 5^4 = 625 =55=3125\uparrow = 5^5 = 3125

Each symbol represents a power of 5.\boxed{\text{Each symbol represents a power of 5.}}

Step 2 — Converting 15

We want to find how many of each power of 5 are in 15. The largest power of 5 less than or equal to 15 is 51=55^1 = 5. We divide 15 by 5. 15÷5=3 with a remainder of 015 \div 5 = 3 \text{ with a remainder of } 0 So, 15 is made up of three 5s. 15=3×515 = 3 \times 5 We use three Square symbols for 15.

15=\boxed{15 = \square \square \square}

Step 3 — Converting 50

We want to find how many of each power of 5 are in 50. The largest power of 5 less than or equal to 50 is 52=255^2 = 25. We divide 50 by 25. 50÷25=2 with a remainder of 050 \div 25 = 2 \text{ with a remainder of } 0 So, 50 is made up of two 25s. 50=2×2550 = 2 \times 25 We use two Hexagon symbols for 50.

50=\hexagon\hexagon\boxed{50 = \hexagon \hexagon}

Step 4 — Converting 137

We want to find how many of each power of 5 are in 137. The largest power of 5 less than or equal to 137 is 53=1255^3 = 125. We divide 137 by 125. 137÷125=1 with a remainder of 12137 \div 125 = 1 \text{ with a remainder of } 12 So, we use one Circle symbol. We have 12 remaining. Now we look at 12. The largest power of 5 less than or equal to 12 is 51=55^1 = 5. We divide 12 by 5. 12÷5=2 with a remainder of 212 \div 5 = 2 \text{ with a remainder of } 2 So, we use two Square symbols. We have 2 remaining. Now we look at 2. The largest power of 5 less than or equal to 2 is 50=15^0 = 1. We divide 2 by 1. 2÷1=2 with a remainder of 02 \div 1 = 2 \text{ with a remainder of } 0 So, we use two Triangle symbols. Combining these, we get: 137=1×125+2×5+2×1137 = 1 \times 125 + 2 \times 5 + 2 \times 1

137=\boxed{137 = \bigcirc \square \square \triangle \triangle}

Step 5 — Converting 293

We want to find how many of each power of 5 are in 293. The largest power of 5 less than or equal to 293 is 53=1255^3 = 125. We divide 293 by 125. 293÷125=2 with a remainder of 43293 \div 125 = 2 \text{ with a remainder of } 43 So, we use two Circle symbols. We have 43 remaining. Now we look at 43. The largest power of 5 less than or equal to 43 is 52=255^2 = 25. We divide 43 by 25. 43÷25=1 with a remainder of 1843 \div 25 = 1 \text{ with a remainder of } 18 So, we use one Hexagon symbol. We have 18 remaining. Now we look at 18. The largest power of 5 less than or equal to 18 is 51=55^1 = 5. We divide 18 by 5. 18÷5=3 with a remainder of 318 \div 5 = 3 \text{ with a remainder of } 3 So, we use three Square symbols. We have 3 remaining. Now we look at 3. The largest power of 5 less than or equal to 3 is 50=15^0 = 1. We divide 3 by 1. 3÷1=3 with a remainder of 03 \div 1 = 3 \text{ with a remainder of } 0 So, we use three Triangle symbols. Combining these, we get: 293=2×125+1×25+3×5+3×1293 = 2 \times 125 + 1 \times 25 + 3 \times 5 + 3 \times 1

293=\hexagon\boxed{293 = \bigcirc \bigcirc \hexagon \square \square \square \triangle \triangle \triangle}

Step 6 — Converting 651

We want to find how many of each power of 5 are in 651. The largest power of 5 less than or equal to 651 is 54=6255^4 = 625. We divide 651 by 625. 651÷625=1 with a remainder of 26651 \div 625 = 1 \text{ with a remainder of } 26 So, we use one Tilde symbol. We have 26 remaining. Now we look at 26. The largest power of 5 less than or equal to 26 is 52=255^2 = 25. We divide 26 by 25. 26÷25=1 with a remainder of 126 \div 25 = 1 \text{ with a remainder of } 1 So, we use one Hexagon symbol. We have 1 remaining. Now we look at 1. The largest power of 5 less than or equal to 1 is 50=15^0 = 1. We divide 1 by 1. 1÷1=1 with a remainder of 01 \div 1 = 1 \text{ with a remainder of } 0 So, we use one Triangle symbol. Combining these, we get: 651=1×625+1×25+1×1651 = 1 \times 625 + 1 \times 25 + 1 \times 1

651=\hexagon\boxed{651 = \sim \hexagon \triangle}

Answer

(i) 15=15 = \square \square \square (ii) 50=\hexagon\hexagon50 = \hexagon \hexagon (iii) 137=137 = \bigcirc \square \square \triangle \triangle (iv) 293=\hexagon293 = \bigcirc \bigcirc \hexagon \square \square \square \triangle \triangle \triangle (v) 651=\hexagon651 = \sim \hexagon \triangle

More questions in FIO

Q1

Suppose you are using the number system that uses sticks to represent numbers, as in Method 1. Without using either the number names or the numerals of the Hindu number system, give a method for adding, subtracting, multiplying and dividing two numbers or two collections of sticks.

Q2

One way of extending the number system in Method 2 is by using strings with more than one letter—for example, we could use 'aa' for 27. How can you extend this system to represent all the numbers? There are many ways of doing it!

Q3

Try making your own number system.

Q4

Represent the following numbers in the Roman system.

(i) 1222 (ii) 2999 (iii) 302 (iv) 715

Q5

A group of indigenous people in a Pacific island use different sequences of number names to count different objects. Why do you think they do this?

Q6

Consider the extension of the Gumulgal number system beyond 6 in the same way of counting by 2s. Come up with ways of performing the different arithmetic operations (+, −, ×, ÷) for numbers occurring in this system, without using Hindu numerals. Use this to evaluate the following:

(i) (ukasar-ukasar-ukasar-ukasar-urapon) + (ukasar-ukasar-ukasar-urapon)

(ii) (ukasar-ukasar-ukasar-ukasar-urapon) − (ukasar-ukasar-ukasar-ukasar)

(iii) (ukasar-ukasar-ukasar-ukasar-urapon) × (ukasar-ukasar)

(iv) (ukasar-ukasar-ukasar-ukasar-ukasar-ukasar-ukasar-ukasar) ÷ (ukasar-ukasar)

Q7

Identify the features of the Hindu number system that make it efficient when compared to the Roman number system.

Q8

Using the ideas discussed in this section, try refining the number system you might have made earlier.

Q9

Represent the following numbers in the Egyptian system: 10458, 1023, 2660, 784, 1111, 70707.

Q10

What numbers do these numerals stand for?

Q11

Write the following numbers in the above base-5 system using the symbols in Table 2: 15, 50, 137, 293, 651.

Q12

Is there a number that cannot be represented in our base-5 system above? Why or why not?

Q13

Compute the landmark numbers of a base-7 system. In general, what are the landmark numbers of a base-n system?

Q14

Add the following Egyptian numerals:

Q15

Add the following numerals that are in the base-5 system that we created:

Remember that in this system, 5 times a landmark number gives the next one!

Q16

Can there be a number whose representation in Egyptian numerals has one of the symbols occurring 10 or more times? Why not?

Q17

Create your own number system of base 4, and represent numbers from 1 to 16.

Q18

Give a simple rule to multiply a given number by 5 in the base-5 system that we created.

Q19

Represent the following numbers in the Mesopotamian system —

(i) 63 (ii) 132 (iii) 200 (iv) 60 (v) 3605

Q20

Why do you think the Chinese alternated between the Zong and Heng symbols? If only the Zong symbols were to be used, how would 41 be represented? Could this numeral be interpreted in any other way if there is no significant space between two successive positions?

Q21

Form a base-2 place value system using 'ukasar' and 'urapon' as the digits. Compare this system with that of the Gumulgal's.

Q22

Where in your daily lives, and in which professions, do the Hindu numerals, and 0, play an important role? How might our lives have been different if our number system and 0 hadn't been invented or conceived of?

Q23

The ancient Indians likely used base 10 for the Hindu number system because humans have 10 fingers, and so we can use our fingers to count. But what if we had only 8 fingers? How would we be writing numbers then? What would the Hindu numerals look like if we were using base 8 instead? Base 5? Try writing the base-10 Hindu numeral 25 as base-8 and base-5 Hindu numerals, respectively. Can you write it in base-2?

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